#[repr(transparent)]
pub struct NonZeroIsize(_);
Expand description

An integer that is known not to equal zero.

This enables some memory layout optimization. For example, Option<NonZeroIsize> is the same size as isize:

use std::mem::size_of;
assert_eq!(size_of::<Option<core::num::NonZeroIsize>>(), size_of::<isize>());

Implementations

Creates a non-zero without checking whether the value is non-zero. This results in undefined behaviour if the value is zero.

Safety

The value must not be zero.

Creates a non-zero if the given value is not zero.

Returns the value as a primitive type.

Returns the number of leading zeros in the binary representation of self.

On many architectures, this function can perform better than leading_zeros() on the underlying integer type, as special handling of zero can be avoided.

Examples

Basic usage:

let n = std::num::NonZeroIsize::new(-1isize).unwrap();

assert_eq!(n.leading_zeros(), 0);

Returns the number of trailing zeros in the binary representation of self.

On many architectures, this function can perform better than trailing_zeros() on the underlying integer type, as special handling of zero can be avoided.

Examples

Basic usage:

let n = std::num::NonZeroIsize::new(0b0101000).unwrap();

assert_eq!(n.trailing_zeros(), 3);

Computes the absolute value of self. See isize::abs for documentation on overflow behaviour.

Example

let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;

assert_eq!(pos, pos.abs());
assert_eq!(pos, neg.abs());

Checked absolute value. Check for overflow and returns None if self == isize::MIN. The result cannot be zero.

Example

let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!(Some(pos), neg.checked_abs());
assert_eq!(None, min.checked_abs());

Computes the absolute value of self, with overflow information, see isize::overflowing_abs.

Example

let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!((pos, false), pos.overflowing_abs());
assert_eq!((pos, false), neg.overflowing_abs());
assert_eq!((min, true), min.overflowing_abs());

Saturating absolute value, see isize::saturating_abs.

Example

let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;
let min_plus = NonZeroIsize::new(isize::MIN + 1)?;
let max = NonZeroIsize::new(isize::MAX)?;

assert_eq!(pos, pos.saturating_abs());
assert_eq!(pos, neg.saturating_abs());
assert_eq!(max, min.saturating_abs());
assert_eq!(max, min_plus.saturating_abs());

Wrapping absolute value, see isize::wrapping_abs.

Example

let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;
let max = NonZeroIsize::new(isize::MAX)?;

assert_eq!(pos, pos.wrapping_abs());
assert_eq!(pos, neg.wrapping_abs());
assert_eq!(min, min.wrapping_abs());

Computes the absolute value of self without any wrapping or panicking.

Example

let u_pos = NonZeroUsize::new(1)?;
let i_pos = NonZeroIsize::new(1)?;
let i_neg = NonZeroIsize::new(-1)?;
let i_min = NonZeroIsize::new(isize::MIN)?;
let u_max = NonZeroUsize::new(usize::MAX / 2 + 1)?;

assert_eq!(u_pos, i_pos.unsigned_abs());
assert_eq!(u_pos, i_neg.unsigned_abs());
assert_eq!(u_max, i_min.unsigned_abs());

Multiply two non-zero integers together. Check for overflow and return None on overflow. As a consequence, the result cannot wrap to zero.

Examples

let two = NonZeroIsize::new(2)?;
let four = NonZeroIsize::new(4)?;
let max = NonZeroIsize::new(isize::MAX)?;

assert_eq!(Some(four), two.checked_mul(two));
assert_eq!(None, max.checked_mul(two));

Multiply two non-zero integers together. Return isize::MAX on overflow.

Examples

let two = NonZeroIsize::new(2)?;
let four = NonZeroIsize::new(4)?;
let max = NonZeroIsize::new(isize::MAX)?;

assert_eq!(four, two.saturating_mul(two));
assert_eq!(max, four.saturating_mul(max));
🔬 This is a nightly-only experimental API. (nonzero_ops)

Multiply two non-zero integers together, assuming overflow cannot occur. Overflow is unchecked, and it is undefined behaviour to overflow even if the result would wrap to a non-zero value. The behaviour is undefined as soon as self * rhs > isize::MAX, or self * rhs < isize::MIN.

Examples
#![feature(nonzero_ops)]

let two = NonZeroIsize::new(2)?;
let four = NonZeroIsize::new(4)?;

assert_eq!(four, unsafe { two.unchecked_mul(two) });

Raise non-zero value to an integer power. Check for overflow and return None on overflow. As a consequence, the result cannot wrap to zero.

Examples

let three = NonZeroIsize::new(3)?;
let twenty_seven = NonZeroIsize::new(27)?;
let half_max = NonZeroIsize::new(isize::MAX / 2)?;

assert_eq!(Some(twenty_seven), three.checked_pow(3));
assert_eq!(None, half_max.checked_pow(3));

Raise non-zero value to an integer power. Return isize::MIN or isize::MAX on overflow.

Examples

let three = NonZeroIsize::new(3)?;
let twenty_seven = NonZeroIsize::new(27)?;
let max = NonZeroIsize::new(isize::MAX)?;

assert_eq!(twenty_seven, three.saturating_pow(3));
assert_eq!(max, max.saturating_pow(3));
🔬 This is a nightly-only experimental API. (nonzero_min_max)

The smallest value that can be represented by this non-zero integer type, equal to isize::MIN.

Note: While most integer types are defined for every whole number between MIN and MAX, signed non-zero integers are a special case. They have a “gap” at 0.

Examples
#![feature(nonzero_min_max)]

assert_eq!(NonZeroIsize::MIN.get(), isize::MIN);
🔬 This is a nightly-only experimental API. (nonzero_min_max)

The largest value that can be represented by this non-zero integer type, equal to isize::MAX.

Note: While most integer types are defined for every whole number between MIN and MAX, signed non-zero integers are a special case. They have a “gap” at 0.

Examples
#![feature(nonzero_min_max)]

assert_eq!(NonZeroIsize::MAX.get(), isize::MAX);
🔬 This is a nightly-only experimental API. (nonzero_bits)

The size of this non-zero integer type in bits.

This value is equal to isize::BITS.

Examples
#![feature(nonzero_bits)]

assert_eq!(NonZeroIsize::BITS, isize::BITS);

Trait Implementations

Formats the value using the given formatter.

The resulting type after applying the | operator.

Performs the | operation. Read more

The resulting type after applying the | operator.

Performs the | operation. Read more

The resulting type after applying the | operator.

Performs the | operation. Read more

Performs the |= operation. Read more

Performs the |= operation. Read more

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Deserialize this value from the given Serde deserializer. Read more

Formats the value using the given formatter. Read more

Converts NonZeroI16 to NonZeroIsize losslessly.

Converts NonZeroI8 to NonZeroIsize losslessly.

Converts NonZeroU8 to NonZeroIsize losslessly.

The associated error which can be returned from parsing.

Parses a string s to return a value of this type. Read more

Feeds this value into the given Hasher. Read more

Feeds a slice of this type into the given Hasher. Read more

Formats the value using the given formatter.

Formats the value using the given formatter.

This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

Restrict a value to a certain interval. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

Serialize this value into the given Serde serializer. Read more

Attempts to convert NonZeroI128 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroI32 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroI64 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroI128.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroI16.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroI32.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroI64.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroI8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroU128.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroU16.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroU32.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroU64.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroU8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroUsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU128 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU16 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU32 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU64 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroUsize to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert isize to NonZeroIsize.

The type returned in the event of a conversion error.

Formats the value using the given formatter.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Converts self into T using Into<T>. Read more

Causes self to use its Binary implementation when Debug-formatted. Read more

Causes self to use its Display implementation when Debug-formatted. Read more

Causes self to use its LowerExp implementation when Debug-formatted. Read more

Causes self to use its LowerHex implementation when Debug-formatted. Read more

Causes self to use its Octal implementation when Debug-formatted. Read more

Causes self to use its Pointer implementation when Debug-formatted. Read more

Causes self to use its UpperExp implementation when Debug-formatted. Read more

Causes self to use its UpperHex implementation when Debug-formatted. Read more

Formats each item in a sequence. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Pipes by value. This is generally the method you want to use. Read more

Borrows self and passes that borrow into the pipe function. Read more

Mutably borrows self and passes that borrow into the pipe function. Read more

Borrows self, then passes self.borrow() into the pipe function. Read more

Mutably borrows self, then passes self.borrow_mut() into the pipe function. Read more

Borrows self, then passes self.as_ref() into the pipe function.

Mutably borrows self, then passes self.as_mut() into the pipe function. Read more

Borrows self, then passes self.deref() into the pipe function.

Mutably borrows self, then passes self.deref_mut() into the pipe function. Read more

Immutable access to a value. Read more

Mutable access to a value. Read more

Immutable access to the Borrow<B> of a value. Read more

Mutable access to the BorrowMut<B> of a value. Read more

Immutable access to the AsRef<R> view of a value. Read more

Mutable access to the AsMut<R> view of a value. Read more

Immutable access to the Deref::Target of a value. Read more

Mutable access to the Deref::Target of a value. Read more

Calls .tap() only in debug builds, and is erased in release builds.

Calls .tap_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_borrow() only in debug builds, and is erased in release builds. Read more

Calls .tap_borrow_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_ref() only in debug builds, and is erased in release builds. Read more

Calls .tap_ref_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_deref() only in debug builds, and is erased in release builds. Read more

Calls .tap_deref_mut() only in debug builds, and is erased in release builds. Read more

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

Uses borrowed data to replace owned data, usually by cloning. Read more

Converts the given value to a String. Read more

Attempts to convert self into T using TryInto<T>. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.